Some thought the 2008 film "The Dark Knight" was too dark for a PG-13 rating. Photo: Reuters

The Motion Picture Association of America has given The Dark Knight Rises a PG-13 rating, meaning Batman fans as young as 13 will be able to buy tickets to the highly-anticipated film without adult supervision.

The Dark Knight Rises, the final film in director Christopher Nolan's Batman trilogy, hits U.S. theaters on July 20. UK film pros are positive that the U.S. PG-13 rating will mean a 12A rating there (which means kids under the age of 12 can attend a screening with an adult).

A report in the Guardian raises the possibility that a 12A rating for the next Batman film could reawaken old debates about whether the material is suitable for younger audiences, especially considering the dark subject matter in the previous film in the Batman franchise, The Dark Knight.

Nolan's upcoming film comes on the heels of recent MPAA controversies. The documentary film Bully, which followed students who were victims of bullying in school and the administrators who failed to help them, was given an R rating because of repeated instances of the F word. Anti-bullying lobbyists joined the Weinstein Co. in protest of the rating, which would have prevented a critical school-age demographic from seeing the film. After a convoluted series of appeals and compromises, the MPAA eventually reduced the R to a PG-13, a week after the documentary's theatrical premiere.

I feel completely vindicated with this resolution, the film's director Lee Hirsch said of the rating change in a statement, the Associated Press reported. While I retain my belief that PG-13 has always been the appropriate rating for this film, as reinforced by Canada's rating of a PG, we have today scored a victory from the MPAA.

Some questioned the PG-13 rating given to the film adaptation of The Hunger Games, the first book in a trilogy by Suzanne Collins that takes place in a post-apocalyptic world in which children are forced to fight each other to the death. Since the books have appealed to readers under the age of 13, parents were debating whether to take their younger children to see the film.

Christopher Ferguson, a professor of psychology and criminal justice at Texas A&M International University, wrote about the matter for Time magazine and said he would watch the movie with his 8-year-old son, while Time film critic Mary Pols wrote in a competing op-ed that the film doesn't feel suitable for anyone under 12.

The release of The Hunger Games adaptation divided some parents of children in the movie's target audience. The film shows the contestants using knives, spears, explosives, and bows and arrows, among other means, in attempts to knock each other out of the competition. There's also blood, such as when one of the characters is killed by a spear deliberately thrown at her by another contestant.

A March report in the Daily Mail claimed that some young people were walking out of showings of The Hunger Games in horror and that some were lobbying to have the film rating raised to 15, which would forbid anyone younger than that age from seeing the film in theaters.

Modern Batman films -- Batman (1989), Batman Returns (1992), Batman Forever (1995), Batman & Robin (1997), Batman Begins (2005), The Dark Knight (2008) -- have all been rated PG-13. A restricted rating given to any of these films would ultimately mean barring a key demographic -- young comic book and movie fans -- from seeing the film in theaters, and thereby making for less box office success.

Arguably, most of these movies merited a PG-13 rating. While they've all had dark elements, the first two films were directed by Tim Burton, who is known for creating movies with dark but also whimsical elements (Alice in Wonderland, Sleepy Hollow, The Nightmare Before Christmas). Batman & Robin, which was directed by Joel Schumacher and starred George Clooney and Chris O'Donnell as the title characters, got mostly negative reviews thanks in part to a flawed plot and costumes worn by the two male leads that featured sculpted nipples.

Then Nolan came along.

The brain behind films such as Memento and Insomnia -- who would later helm Inception -- brought audiences Batman Begins in 2005, the first of three movies he would make about the comic book superhero. Nolan's take on the Batman franchise was considerably darker, but the film managed to hold on to its traditional PG-13 rating without raising too many eyebrows.

Not so for the The Dark Knight in 2008.

The film kept most of the original cast from the previous film and brought a highly-anticipated addition: Heath Ledger in the role of the Joker. That role was previously played by Jack Nicholson with a dark but ultimately humorous angle. Ledger's joker was entirely different. The actor described his Joker to the New York Times in 2007 as a psychopathic, mass-murdering, schizophrenic clown with zero empathy. His performance won him a posthumous Oscar.

In the film, the Joker reveals a penchant for self-mutilation, makes a pencil disappear by pointing it into a table and slamming a man's head on it, attempts to maul Maggie Gyllenhaal's character and cut her (but not before grabbing her face and teasing her with a knife), and blows up part of a hospital.

With all this, The Dark Knight still retained a PG-13 rating, plus a 12A rating in the UK. This was criticized at the time by members of Parliament, according to a 2008 report in the Guardian. The MPs thought the rating was too low and criticized the ones who dished it out -- the British Board of Film Classification. The Guardian cited a letter written to the Times by former UK Conservative party leader Iain Duncan Smith. He expressed surprise that The Dark Knight wasn't given at least a 15 on the UK movie ratings scale.

It is a relentlessly violent film, filled with dark themes, and as I left I wondered what the board could possibly have been thinking, he wrote, according to the Guardian report. There is no way that a parent could have been guided by the classification and realised what they were about to see.

Nolan's upcoming Batman film will no doubt be a hit thanks to his gift for action storytelling and stars like Anne Hathaway, who will play the role of Selina Kyle (ie Catwoman). But since production details have been kept under wraps, it's too soon to tell if The Dark Knight Rises will give rise to nightmares.